Experimental determination of motion-induced force coefficients of long-span bridge models in a water channel

Wind loads on a bridge may be classified into two types: the buffeting loads and the self-excited loads. The research reported in this thesis is concerned with experimental determination of the self-excited loads in the frequency domain, in particular, their non-dimensional coefficients, called flutter derivatives. The experiments were conducted in a water channel with water substituting for air. Five bridge-section models of different shapes were tested, each of which was driven to move harmonically by linkages, and the forces on the linkages were measured to determine the fluid loads. A thin-plate model, simulating an airfoil, was also tested and the results were compared with those obtained from the thin airfoil theory. The setup of the experiments and data acquisition, processing and analysis are presented herein.